Bar clamps are well known tools used in many carpentry and handicraft applications. Bar clamps generally comprise a pair of clamping jaws that slide along a bar. A workpiece may be clamped between the jaws by abutting the jaws against opposite sides of the workpiece, and then tightening the jaws against the workpiece, such as by repetitive squeezing of a hand-held trigger mechanism.
The bar clamp may also be used to spread objects apart. This may be accomplished by turning around the clamping jaws 180°, which reverses the advancing movement of the jaws along the bar towards each other into a retreating movement away from each other. The objects may be spread apart by abutting the jaws against the appropriate surfaces of the objects, and then moving the jaws in the spreading direction, such as by repetitive squeezing of the hand-held trigger mechanism.
U.S. Pat. No. 6,382,608 to Michell describes a bar clamp having a fixed jaw and a movable jaw opposing the fixed jaw, where the fixed jaw and the movable jaw each include two jaw pads facing in opposite directions. The fixed jaw and the movable jaw are not at the same height relative to the bar. Two ratchet means are provided for advancing the movable jaw in mutually opposite directions along the bar.